Power transmission units



POWER TRANSMISSION UNITS Filed Feb. 6, 1957 4 Sheets-Sheet 1 March l5, 1960 w; c. RHODES ET A'. 2,928,513

POWER TRANSMISSION UNITS Filed Feb. 6, 3.957 4 Sheets-Sheet 2 March 15, 1960 w. c. RHODES ET AL l 2,928,513

POWER TRANSMISSION UNITS Filed Feb. 6. 3.957

4 Sheets-Sheet 3 March l5, 1960 l w. c. RHODES ET AL 2,928,513

POWER TRANSMISSION UNITS Filed Feb. e, 1957 4 sheets-Shea' 4 POWER TRANSMISSION UNrrs Walter C. Rhodes, Chatham, NJ., and Charles B. Kirkham, Montgomery, N.Y., assignors to Airborne Accessories Corporation, Hillside, NJ., a corporation of New Jersey Application February v6, 1957, Serial No.' 638,654

12 claims. (cl. 192-4) tes Patent VO For the most part, these include bulkiness, excessive I Weight, ditlcultand slow control, extensive maintenance and limited applications, particularly the inability to meet the need for automatic and accurate positioning of heavy loads.

It is a primary object of the invention to overcome the above stated disadvantages of currently available transmissions by the provision of a small, compact, reversible, gear transmission unit completely encased in a housing and having electrically controlled clutches and a brake -included therein, and whose parts, by vreason of their ruggedness and the operation of the mechanical elements in an oil lilled and sealed environment, require no adjustment for the life of the transmission unit.

A further object of the invention lies in the provision of suitably positioned oil seals within the unit housing to separate the electromagnetic clutches and brake from oil filled portionsl ofthe housing thus permitting operation of the gears in an oil bath and lcontributing tothe dur ability, long life and trouble-free operation of the transmission unit.

Another object of the invention is to provide a reversing, gear transmission unit electrically controlled to which may be applied synchro transformer and amplifier circuits so that by means of a closed servo loop, accurate positioning of a heavy load may be accomplished either manually or by means of automatic control directed by an associated machine. Y

VThe novel features that are'considered characteristic of the invention are set forth with particularity `in the appended claims. The invention itself, however, b'oth as to its organization'and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specic embodiments when read in connection with thefaccompanying drawings, wherein like reference characters indi `cate like parts through the several iigures and in Which:

Fig. 3 is an end elevation of the transmission unit looking toward the output shaft;

Fig. 4 isa top plan view of the terminal box alone vwhich houses certain of the electrical controls ofthe transmission unit;

Fig.`5 is a schematic wiring diagram showing the electrical circuitsNfor control of the transmission unit;

Patented Mar. 15, '19690 Fig. 6 is a simplified sketch of the transmission gearing, clutch and brake arrangement; -l

Fig.v 7 is an end elevation of a transmission unit modified to include accurate output positioning means;

Fig. 8 is a schematic wiring diagram for the modified transmission unit vshown in Fig. 7, and

` Fig. 9 is a reduced fragmentary vertical section similar to Fig. 2 showing the modification to add a synchro transmitter.

` Referring now more particularly to the drawings@v specifically to the embodiment of the invention illustrated in Figs. 1-6, there is shown a transmission unit l to which may be directly coupled a driving motor M. The drive l motor, shown in dotted outline, is three horsepoweror larger and, if desired, may be indirectly coupled to the transmission unit. i

The transmission unit 1 is housed in a generally barrelshaped casing 2 whose openends are closed by end bells 3 and 4. The end bells provide openings for journaling the input and output shaft as shall hereinafter be described. Additional journals are provided for these shafts and the Vinternal gearing by member 5 disposed Within and integral with the casing 2 and dividing the casing roughly into` two' compartments A and B, the latter of which retains oil for splash lubricationof the shafts, bearings and gears. l

The member 5 comprises a horizontallydisposed-cy-- lindrical portion 6 intersecting at'right angles horizontally with a second cylindrical portion 7.- The portion 7 has integral cylindrical extensions -8 of largerldiameter at its 'ends which are partly cut away for ease of assembly purposes and which partially enclose the clutches. A web 9 connects cylinders 7 and 8. A vertically disposed central ange 10 (Fig. 2) on journal member S serves to complete the sealing of chambers A 'and Bafrom `each other. l

The power input shaft 11 is provided with a key slot 12 externallyof the casing and is journaled in ball bearings 13 and 14, respectively held in'bell 3 and portion 6 of member S. The bearings 13V are packed with grease but all other bearingsto be described may be lubricated by an oil supply in chamber B. The raceways of Vbearing 13`are retained in place 'by rings `15'whch are partially embeddedV in shaft 11 and end bell 3. The same means may be employed for retaining many of the other bearings and oil seals in the assembly to be described,V but the outer raceway of the bearing 14 is shownras being retained by a ring 6 boltedV (Fig. 2) Vto the end of the cylinder 6. A bev-el gear 16V is secured to the inner end of input shaft 11, Within chamber B, by a key 17. The open end 6 of journal member 5 is closed by an annular oil seal 18.

Ahorizontally disposed shaft 19 extends from side to Aside within the casing Zandthrough the cylinders 7 and stantially abut the bearings 22 and 23 to prevent escape `of oil from the assembly of gears and bearings on shaftY l Apair'o'f similar electromagnetic clutch assemblies 30,`

30 are,` supported in chamber A within casing '2 Yand surround shaft 19, Yasshown in Figs. 1 and 6. Each clutch comprises an armature 27, a rotor 28 andl a ield 29.V `The hubs of gears 20 and 21 are provided withV K splines 32 to guide the similarly splined armatures 27 Ain limited sliding movement along the axes of the gears 4@they gearsfzo-and 21, `said shart19 wiufnetrere with; i

Y einer or the gearsumn one of the tti/'minimes 30130'. 'fis' energized. "flhisiwill causethe"correspondingclutch and shaftaf19 toward` their corresponding rotors., Each rotor 28 is fixed to shaft 19x and has an annulus of friction material embeddedm the faceV of the rotorrwhich frictionally engages the Varmature uponelectricllycntrolled magnetic attraction.A EachVV clutchiield `29 fispro- :vided Withwire'cils-for passage.ofelectriccurrent and `is fastenedto the `unit casing 2 asby 'means ofdowel fantasme;

`pins Siwhich tit into notches `provided inlperipleral Y flanges of the clutch ields. WhenoneA ofthe clutchfields fis energized, the corresponding armature27 will `be atfV tracted to its rotorZS andcauseit to rotate Aalong with the shaft 19 to which the -rotor is fastened. j 3A brake Y31similarto the described :clutches-is ,posi` l tioneti;` outside ofthel casing'Zbut,withiuajprotective housing "35, The brake held. 29 is also `fixed to the :housmounted on a small'splined hub 34 xedto Shahid-91am is; free toslide along the hub whenzattractedto .theubfaireV shoe. '1-`l1u,sthe` brake armature-27' will'rotate withzehaft 19 `until, the brake `isjene'rgzed a't Awhich ,time ititWi-llzbe Y i 4 Y armature 27, Vwhich "rotates with gear `20` or 421, to `be attracted to its VmatingV rotor.4 28 and through the latter, turn shaft 19 in the'desired direction. Reversal` of direction of shaft 19 is obtained` by kenergizing the other fclutch. Since the brakeV armature 27' turns with shaft 19,"energizingthe brake1eld-.29' will cause that arma-A i ture to be attractedto'thefxed brake shoe 428', stopping the rotation of shaftf19. `Shaft 19,` while-rotating in either a :clockwise or counterclockwisevdirectionthrough` permanently-rneshedjbevel `gears 36 and 37, drives the t .output shaft inagcorresponding"direction 'through the train of reduction spur gears 38, 42,43 and'44ij Of course,on1y;one clutch 3,0 `or310'v should be ener` gizedatagivntme, and the brake 31 should not be enc ergized while on'of the clutchesrjis energized. Provisions l are made in the circuit connections to insure these condition's', as shown in the schematic wiring diagram of Fig 5l i-njioperator controlling :the :transmission unit moves `switeh i1n1a87 Vto contact gtermin'al :'85,n the brake 3,1` isjenergized from one-side of the,A.,C."power f source, ,throughfconductor'lm rectifier 72, conductor'76,

magnetically vattracted to the anchoredrbrakejshoe and will stop the shaft 19. YAt the :end ofsha'ft319 oppsite the brake 31, Va `plate 35'c1oses the opening .infcasingrzg A bevel `gear 36` is fastened` to and "rotateswith shaft 19 to drive a bevel gear 37. Integral with gear-37 on -v i the opposite end offthe 'same hub i's `-a 'spur"tgear"38. A These gears-are journaled in tubular part 6 of member 5 by a ball `bearing 39androtate onan outputshaft 7:40,V

`being mounted thereon by inner Vrollerbeaings 4'1.A VThe switch arm S7,` terminal 85, conductor 82, rrheostato,`

adjustingcontact 163'., conductor'79, lthe `lield .winding 29' of the Cbrake,;conductor,77 rectifier :75, `conductor`71 and r'eturnzzto othersid'eyof 'the power source. When it `is f Ldesiredto rotate the outputshaftinaclockwise direction,

:gear 38,; as shown l,in .Figs.f2 and 6, Vdrives a spur gear vreduction train comprising gears 42,443 'and v44,*the last,-

being `fastened to and driving'the output shaft 40. Gears 42 ,and` 43fare-formed integrally on the same hub 45 whichfisjou'rnaledat vone end in a 4ball bearing 46 cak riedby `portion 10 of rnernberrS. "Thefother end of hub 45 is -journaled in ballrbearing 47 carried in `an annular Well 48 oifset from the center of end bell 4. Output f'sliaft- 40 is provided witha key' slot 49 externally of.' the end bell 4 and is journaled therein by meansof ball bearing 50. VAn oil seal 51 seals the endi'bell journal opening ofyheavy loads.4 Y, If'zit risfdesired toaccurately` position ,a load, :thesame vbasicgtransmission zunit may` bel used .swithsme' modification-'of auxiliary partsland the addiarouudshait 40 and retainsoil within'theendbell and chamber B. In the arrangement shownpftlieoutpt shaft 401sc'o-axialtwith the input shaft 11. "1

The member Sis, by means of extensions 52 andf53 ofirregular shape. to portion 10; adapted to` close openings at the top and bottom of casing 2. The'bottom ex-` tension *S-Z'carries integral feetV 54 yfor `supporting the f `transmission unit.- An oil drain opening`55," normally i closedA by a4 screw/,uis provided through `thebotorrr of ,Y extensionfl An oil till opening, notvisiblein the" ii'gl:uresfis provided in the upper `part of easingZ.V

p The Upper. extension'53 is formed into 1a rectangular housmg `portion l56 above the transmissionY chamber Bw' andhas van opening inits upper wall which is "closed` by the switcl1'87 Visrnovedto contactjterminal l84 de,-`

energizing the `brake 31 `and encrgizingfone-'clutch 30 Vthrough conductor 81,"rheostat 59, adjustment contact Y 62.,conductorr.78 :and 'the (field 29roffthezclockwise clutch.` Similarly, Awhen itis 4desired to frotate the :output shaft in the opposite direction, `the `switch arm' 87A need only he moved tolcontactxtemnal-86` and make the circuit through conductor "8,3, `rheostat 161; *adjustment Contact 64', conductor. 80^and the iield` 29 tof thefcounterclockwise clutch 30. In' this manner, `operationzof switch 68 :causes'the.outputshaft 40to turn Vin eith'er direction or to bequi'ckly :stoppedwhile drivingla `heavyfload. y

. lThe-transmission asdescribedgabove isadapted to per- ;foim'general'purpose iindustrial tasks involving movement cation is broadly Villustrated in Figs. 7, 8 `and 9.3 l/kn` i, 'laltemating' ic'urrent .tachometer generator '91" :is gdire'ctly M'synchro transmitter? 93 4is `mounted within chamber yAras shown in z-Fig. '9; Thepange 10-'a`nd bell 4,as shown'in Figli, are

; ,'providedavithcylindrical-wellsr110and `'114,'rrespectiv'ely,

` ianda-rtoiiaccmmodate `'the transmitter .93; the well .1:10 is a removable ,cover plate 57.V `VWithin-fthe housings-'56and` A `free from access of oilin chamber Bfare contained 'tltioseY fcircuit elements lnecessary vfor electrical control `ofltlie clutches and brake. Referring particularly to v'2 and 5, these elenmnts'v include a terminalV plat'e'SSQthree rheostasxsa; 6o and `61 each Y.fnijustrable by ermsrnn-.` zscrewsrz; 63an'df64, respectively, a full wave-*bridge- Vmanner-sh'ownin Fig. `5, and accessfcables 66 and' -an external power source and a control'switch 68.

. The `,described embodiment shown-in Figsilil-b irneshed `'to gear 16 Vwill rotate `in Voppositedirectionsiwith rectifier 65, associated ,wiring forconnecting thesen the] Anexternalfcontrol amplier 'isrconnected t connected? tjolthe amplifier bya cable i103.V 1 i Thestator windings 96H and '97 of veach of the'synchro i t'ransmittersV 9 31 and L89 are connected Ain "Y zand `each ffree i l end is 'connected to -thejcorrespondingfree "ends `of the;

109 (Fig..s) ifwhe1 1 thus egnneewd, aryelmge Voutput .gwillf berhaydiwhieh Iis i proportor'ral"to'itherelativeA fangle i t'etweenj theV synchro .transmitter `.9a and; theV .control transformer 89: In other words, if thetran'smissionoue the transformer is a minimum. Taking this point as an arbitrary reference, if the control transformer shaft 90 is rotated in leither direction from this point, the voltage output will be proportional to the angular displacement from the reference point and will be proportional to the relative angle between control transformer 89 and the transmission output shaft 40. This error voltage across coil 95 is amplified and made to energize the proper clutch in the transmission, by means of relays, not shown, to rotate the output shaft 40 and synchro transmitter 93 in such direction as to cause its error signal voltage to disappear. When this happens, the relays will deenergize the clutch and energize the brake so as to stop vthe output shaft 40. The amplifier 88 also senses the error signal supplied from the control transformer 89, ydetermines whether it isA clockwise or counterclockwise from the zero position and operates relays" that energize the proper clutch to turn the transmission shaft 40in the appropriate direction for neutralizing the error signal as well as to operate the brake. Y

The operation of the system is stabilized by use of th feedback tachometer generator 91. The output of this generator is mixed with the error signal from the control transformer 89 by means of synchro transmitter rotor winding 94 and fed to the amplifier 88 via conductors 101 and 102 in such way as to provide damping of the transmission. Stated in another manner, if a transmission output shaft 40 is driving toward a certain desired stopping position, the tachometer generator circuit will Y deenergize the 'associated clutch sufficiently beforehand so that the output shaft can be stopped by the brake at the exact position desired without being carried beyond by the inertia of the transmission. Movement of the control transformer shaft 90 is practically effortless but the transmission output shaft will follow while handling a heavy load. Thus, the operator has means for effortlessly and accurately controlling the positioning of a heavy load in either direction. Automatic rather than manual operation may be obtained by directly coupling shaft 90 of the transmitter 89 to an associated machine so that control will follow the direction of such machine.

It will be apparent-from the above that the described v invention provides an extremely useful, general purpose,

reversible transmission which is very compact and durable and is possessed of numerous other advantages. The overall dimensions of a transmission capable of driving a three horsepower load are only 13 inches by 171/2 inches. This compactness is obtained by journaling certain of the gears within one another and by journaling parts of the clutches on gear hubs. The gears, shafts and bearings are splash lubricated within the transmission casing for long life and reduced maintenance; yet the electrical parts, wiring and clutches are separated completely from access of the oil by use of oil seals and by the configuration of shaft and gear supporting member 5. It should be understood, however, that, if desired, electromagnetic oil clutches and brake may be utilized instead of the dry clutch-and brake assemblies described, in which case, the oil seals and journal member 5 may be modiiiedto vpermit access of oil to the clutch and brake assemblies. The clutches and brake are so mounted with fixed fields as to require no brushes or slip rings. By use of relatively minor modifications and additions of servo loop circuit elements, the transmission is adapted to accurately position loads either manually or by direction of an associated machine.

Although certain specific embodiments of the invention have been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted lexcept insofar as is necessitated by the prior art and by the spirit of the appended claims.'

What is claimed is:

l. A compact transmission unit comprising a power input shaft having a bevel gear, a driveu shaft at right anglesto said input shaft, a pair of gears driven in opposite directions by said bevel gear and journaled on said driven shaft, a pair of electromagnetic clutches each having a rotor fastened to said driven shaftand a stationary field coaxial with and surrounding said driven shaft, an

electromagnetic brake having an armature fastened to said driven shaft and a` stationary field and brake shoe coaxial with said driven shaft, a pair of clutch armatures slidably mounted on said pair of gears each of which is coupled to rotate with its corresponding gear, means for selectively energizing one of said clutches or said brake so as to drive said driven shaft in a desired direction or stop said drive shaft, respectively, an output shaft in alignment Vwith said input shaft, a train of reduction gears operably connecting said-driven shaft to-said output shaft, a housing encasing said driven shaft, said gears and said electromagnetic clutches, and partition means within said housing separating said gears from said vclutches whereby v to prevent access to said clutches of oil surrounding said gears. l

2. A'transmissionunit as defined in claim l wherein one gear of said train of reduction gears is journaled on and is to rotate about said output shaft as an axis.

3'. A transmission unit as defined in c1aim.l ,wherein one gear of saidtrain-of reduction gearsiskeyed to said driven shaft between said pair of gears.

4. A transmission unit comprising a housing, a power input shaft and an output shaft mounted in axial alignment and journaled in bearings held in openings of said housing, an auxiliary journaling member supported within said housing and having a cylindricalportion for joursaid driven shaft 'being journaled in said second cylin-v drical portion, a bevel gear on said input shaft, a pair of gears'driven in opposite directionsjby said bevel gear and journaled on said driven shaft, a pair of electromagneticclutches each having a rotor fastened to said driven shaft Vand a stationary field, an electromagnetic brake having an armature fastened to said driven shaft and a A stationary field and brake shoe, a pair of clutch armatures slidably mounted on said pair of gears each of which is coupled to rotate with its corresponding gear, means for selectively energizing one of said clutches or Vsaid brake so `as to drive said driven shaft in adesired direc-- tion or stop said driven shaft, respectively, a train of reduction gears connecting said driven shaft to said output shaft, one gear of said train of reduction gears being journaled on and to rotate about said output shaft as an axis, and said auxiliary journaling member being provided with extensions `which divide the interior of said housing into separate compartments one of which contains said electromagnetic clutches and the other of which contains oil forsplash lubrication of said shafts and gears.

5.v A transmission unit as defined in claim 4 wherein a plurality of annular oil seals are provided about the said shafts and within' the journal openings of the said auxiliary member to insure retention of oil in the said oil compartment free from access to said electromagnetic members.

6. A transmission unit as defined in claim 4 wherein said auxiliary journaling member is provided with an` additional extension of rectangular vshapeA which projects above and closes the top of said transmission housing, said additional extension housing circuit elements electrically connecting said clutches and brake to a source of electric power.

7. A transmission unit comprising a housing, an input shaft and an output shaft journaled in bearings held in openings in said housing, an auxiliary journaling member supported within said housing and having a rst portion for journaling said input and output shafts, a driven shaft mounted at right angle to said input and output shafts within said housing, a second portion on said aux- 17, iliary member, saididriven Vshaftgbeing journaled in said second portion, gearineans `for imparting motion from said input shaft yto said 1driven Yshaft in either Yoftwo directions, 'additional gerrneansffo'r Yconnecting Vsaid driven shaft `to saidroutputshaft, electromagnetic clutch and brake meansrincludingi'jfrictiondiscs mounted onsaid driven shaft for selectively controlling Yits direction of movement lor s toppi 1 1g 'suchmovement respectively, and saidauxiliaryfjurnaling n'e'mber being providedA with a third portion which dividesY the interiorv of said housing into separate compartments `one tif-which` contains said Y electromagnetic clutch'rneanswand` friction `discs from l which oilis j excluded andi thefotherlof `which contains oil for splashluhrication*Qfsaidhafts `and gear means. 8f 4A `transrn'ission unit comprising a housing, an'input shaftV entering said housing, 1a` driven `shaft, arr-auxiliary f journaling memherwithin the housing having portions :for

' 'journaling said 'inputand .driven shafts, kgear means forg imparting motion `fromfsaid input vshafttosaid driven shaft, electromagnetic clutch andbrake means including friction discs mounted on saiddrivenshaftfor selectively'- controlling its movementjor 4stopping said divenshaft,

respectively, said auxiliary `journaling member Y being pro` vided ,with a`portion which dividesthe` interior of saidA Y housing into separate compartments one of `vvhich contains said electromagnetic clutch means from which oil `is excluded and the other ofwhichrnay beprOVided with and a stationary eldand-,brake shoe, a `pair of clutch armatures V'slidably mounted on said pair of gears each of which .-is coupled to rotate with its corresponding gen voutpnt llshaft, inear'is4 for operably connecting said driven shaft to said 'output shaft, a `synchro transmitter mechanically coupled tosaidloutputzshafnalsynchro Corn` l trol transformer'locatedgat `a-remoteposition, a servo loop circuit 1:onnectng jsaidV synchro transmitter electri-` cally `to saidicnti'oltransmitter, and electric `circuit means Vfor selectively energizing saidclutc'hes and Abrake yin respouse Vto inovementof the shaft `of said control: trans-` mitter to accurately drive said output shaft to a desired t position. l

l2. A` combination transmission unitasdened in claim '511 comprising a tacliometei Vgenerator mechanically Acoup'ledfto said driven shaft and an amplifier remote from oil for splash lubricationv of said shafts andg'ear means.

Q9, `A"tra`nsmission unit comprisingahosingfan input 10; A transmission unit comprising in combination a shaft entering said; l 1 ousing a driven shaft,` a-prtitiorrin said-housingWhicldivides the housing A'intrfseparate oil 1 sealedlcompartments, gearV means for imparting motion" fromsaid input shaft to said driven shaft in o ne ofsaid t compartments, i and electromagnetic Ameans including friction discs mounted in'said vother compartment -foi-selectively controllingA movement ofthe driven shafti power input shaft having a bevelsgear, adrivenshaftat rghtangle to said inpnt shaft, a pair of` gears driven in opposite directions by`said bevel gear Vand, journaled on Y said driven shaft, a pair of electromagneticgclutches each having a rotor `fastened to saiddriv'en shaftl and 'a staf tionary held coaxial with and surrounding Asaiddriven shaft,jan electromagnetic brake having anarmature fastened to said drivenrshaft and a'stationary eldand brake shoe `coaxial with said driven shaft, apair of clutch armaformer locatedat a remote position, a -siervo loop circuit connecting said synchro transmitter electrically"to said control transmitter, and electric circuit means for selecturesslidably mounted; on `said p air of gears each ofY which is coupled torotatewith itscorrespondng gear, an outputshaft in alignment with said input shaft, 4aftrain. j of reduction gears operably connectingsaid idriyenshaftto said output shaft, a vsynchro transmitter mechanically coupled to saidcutput'shaft, a synchro contro1'trans--l said transmission'unit forming part o f *said `eleotr'ic circuit means for selectively energizing said clutchesand brake,

and means for -niixing the electricalfoutpu of saidtachofnieter generatorlwith afsignalfrfom sidcontrol'tansformer l f inthe rotor Windingof said;synchroftransmitter *andV feeding the result tosaid amplifier for deener'gizing nan approl priateV c ltch to prevent overdrivingof desired position because of inertia `of sidtransmissionunit'.

` ReferencesCited. in the `tile of Ithis patentl i f y 'UNITED STATES PATENTS t Mayer ocres, .1395

' 1337745 nr`47h; Apr. 26, 1994;'Germany. 

